The present invention relates to an integrated circuit for generation of sound by means of an electronic apparatus, and in particular to a large scale integrated circuit (LSI) for an electronic apparatus by which the input and output of sound may be obtained synthetic speech generated, and which also includes key input/output apparatus and display apparatus.
In recent years, television games in which the sound of cannons is heard, electronic calculators and timepieces which play melodies, pocket learning devices and electronic calculators which emit human voices, automatic vending machines, and other types of electronic apparatus which emit sounds have made their appearances one after the other. These types of products have been, in part, responsible for the development of LSI technology and in the furthering of synthetic speech generation techniques.
A synthetic speech apparatus used in electronic equipment for sound generation is basically of the type shown in FIG. 1, which is comprised of a ROM 1, in which voice data is stored, and a speech synthesizing circuit 2 which synthesizes a voice signal from this data, with a control circuit 3 which controls the starting and stopping of the synthesizing procedure and the readout from ROM 1. The speech synthesizing circuit 2, from a general point of view, is usually made up of a special synthetic speech LSI, which is used as one of the parts of the speech synthesizing section of this synthetic speech apparatus. Therefore, in the case where this LSI comprises, for example, an element of an electronic calculator which converts calculated formulas, and results, into information in the form of speech (FIG. 2), a microprocessor 4 generally controls the primary key input, the operation, and the display, and this microprocessor develops information in the form of speech from the instruction signal to be provided a specialized speech synthesizing LSI 2.
However, considering the scale of apparatus involved in speech generating electronic calculators and timepieces from the aspect of the configuration of the whole system, the circuit includes a relatively large device portion devoted to speech synthesis as compared with the primary function control circuit. There is considerable demand for a miniaturized compact unit, such as a speech generating electronic calculator which is small enough to be held in the palm of the hand.